AIM: To investigate effect of body dimensions obtained from localizer radiograph and transverse abdominal computed tomography(CT) images on Size Specific Dose Estimate. METHODS: This study was approved by Institutiona...AIM: To investigate effect of body dimensions obtained from localizer radiograph and transverse abdominal computed tomography(CT) images on Size Specific Dose Estimate. METHODS: This study was approved by Institutional Review Board and was compliant with Health Insurance Portability and Accountability Act. Fifty patients with abdominal CT examinations(58 ± 13 years, Male: Female 28:22) were included in this study. Anteriorposterior(AP) and lateral(Lat) diameters were measured at 5 cm intervals from the CT exam localizer radiograph(simple X-ray image acquired for planning the CT exam before starting the scan) and transverse CT images. Average of measured AP and Lat diameters, as well as maximum, minimum and mid location AP and Lat were measured on both image sets. In addition, off centering of patients from the gantry iso-center was calculated from the localizers. Conversion factors from American Association of Physicists in Medicine(AAPM) report 204 were obtained for AP, Lat, AP + Lat, and effective diameter(√ AP * Lat) to determine size specificdose estimate(SSDE) from the CT dose index volume(CTDIvol) recorded from the dose reports. Data were analyzed using SPSS v19. RESULTS: Total number of 5376 measurements was done. In some patients entire body circumference was not covered on either projection radiograph or transverse CT images; hence accurate measurement of AP and Lat diameters was not possible in 11%(278/2488) of locations. Forty one patients were off-centered with mean of 1.9 ± 1.8 cm(range: 0.4-7 cm). Conversion factors for attained diameters were not listed on AAPM look-up tables in 3%(80/2488) of measurements. SSDE values were significantly different compared to CTDIvol, ranging from 32% lower to 74% greater than CTDIvol. CONCLUSION: There is underestimation and overestimation of dose comparing SSDE values to CTDIvol. Localizer radiographs are associated with overestimation of patient size and therefore underestimation of SSDE.展开更多
A survey involving 6103 participants from five Chinese provinces was conducted to evaluate the threshold value of urinary cadmium （UCd） for renal dysfunction as benchmark dose low （BMDL）. The urinary N-acetyl-13-D...A survey involving 6103 participants from five Chinese provinces was conducted to evaluate the threshold value of urinary cadmium （UCd） for renal dysfunction as benchmark dose low （BMDL）. The urinary N-acetyl-13-D-glucosaminidase （UNAG） was chosen as an effect biomarker. The UCd BMDLs for UNAG ranged from 2.18μg/g creatinine （cr） to 4.26μg/g cr in the populations of different provinces. The selection of the sample population and area affect the evaluation of the BMDL. The reference level of UCd for renal effects was further evaluated based on the data of all 6103 subjects. With benchmark responses （BMR） of 10%/5%, the overall UCd BMDLs for males in the total population were 3.73/2.08 μg/g cr. The BMD was slightly lower in females, thereby indicating that females may be relatively more sensitive to Cd exposure than are males.展开更多
This paper introduces the resident’s additional dose in bone-coal mining areas. The increase of the annual additional effective doses accepted by the residents living in the carbide-brick houses, the staffs working i...This paper introduces the resident’s additional dose in bone-coal mining areas. The increase of the annual additional effective doses accepted by the residents living in the carbide-brick houses, the staffs working in the car-bide-brick houses and the miners working in the bone-coal mining areas of Hubei, Hunan, Jiangxi, Zhejiang and An-hui Provinces is caused by the rising of environmental radioactive level. The investigation of natural background ra-diation in the bone-coal mining areas indicated that both mining and utilizing bone-coal cause the rise of environ-mental radioactive level. The ranges of the annual additional effective dose accepted by the residents, staffs and min-ers is 1.9—6.8 mSv, 0.5—2.0 mSv and 8.2—71 mSv, and with an average of 3.8 mSv, 1 mSv and 40 mSv, respec-tively. The annual additional effective doses accepted by part residents and staffs exceed the dose limit of 1 mSv for public exposure, and part miners exceed the dose limit of 20 mSv for occupational exposure. And the contribution of dose caused by inhaled radon to the total additional effective dose is over 76%.展开更多
目的:比较容积CT剂量指数(volume CT dose index,CTDI_(VOL))及基于水当量直径的体型特异性剂量估计值(size-specific dose estimate based on water equivalent diameter,SSDE_(WED))在衡量儿童头颅CT辐射剂量中的差异性,并分析CTDI_(V...目的:比较容积CT剂量指数(volume CT dose index,CTDI_(VOL))及基于水当量直径的体型特异性剂量估计值(size-specific dose estimate based on water equivalent diameter,SSDE_(WED))在衡量儿童头颅CT辐射剂量中的差异性,并分析CTDI_(VOL)、SSDE_(WED)与曝光量、水当量直径(water equivalent diameter,WED)的相关性,以为临床检查中儿童头颅CT辐射剂量衡量提供参考。方法:回顾性分析2021年1—12月于某院进行头颅CT检查的1297例患儿的临床资料,根据年龄将患儿分为≤1个月组、>1个月~4岁组、>4~10岁组、>10~15岁组。记录患儿的曝光量、年龄、CTDI_(VOL)、剂量长度乘积,并计算WED、转换因子及SSDE_(WED)。比较CTDI_(VOL)与SSDE_(WED)的差异;建立CTDI_(VOL)、SSDE_(WED)与曝光量、WED的回归模型,并采用Pearson分析CTDI_(VOL)、SSDE_(WED)与曝光量、WED之间的相关性;对比国内诊断参考水平(diagnostic reference level,DRL)、欧盟DRL及本医疗机构诊断参考水平(local diagnostic reference level,LDRL)的差异。采用SPSS 25.0统计学软件进行分析。结果:患儿头颅CT的CTDI_(VOL)为(9.22±1.63)mGy,SSDE_(WED)为(8.14±0.84)mGy,CTDI_(VOL)较SSDE_(WED)高13.27%,差异有统计学意义(t=47.66,P<0.001)。CTDI_(VOL)、SSDE_(WED)与曝光量、WED均呈正相关关系(P<0.001);CTDI_(VOL)、SSDE_(WED)与曝光量、WED回归模型拟合性较强(R^(2)为0.58~0.99)。与国内DRL及欧盟DRL比较,LDRL均处于较低水平。结论:在儿童头颅CT辐射剂量衡量中,相较于CTDI_(VOL),SSDE_(WED)对辐射剂量的衡量更准确。同时定期对医疗机构的DRL值进行统计更新并优化检查参数,是减少辐射剂量的重要方式。展开更多
文摘AIM: To investigate effect of body dimensions obtained from localizer radiograph and transverse abdominal computed tomography(CT) images on Size Specific Dose Estimate. METHODS: This study was approved by Institutional Review Board and was compliant with Health Insurance Portability and Accountability Act. Fifty patients with abdominal CT examinations(58 ± 13 years, Male: Female 28:22) were included in this study. Anteriorposterior(AP) and lateral(Lat) diameters were measured at 5 cm intervals from the CT exam localizer radiograph(simple X-ray image acquired for planning the CT exam before starting the scan) and transverse CT images. Average of measured AP and Lat diameters, as well as maximum, minimum and mid location AP and Lat were measured on both image sets. In addition, off centering of patients from the gantry iso-center was calculated from the localizers. Conversion factors from American Association of Physicists in Medicine(AAPM) report 204 were obtained for AP, Lat, AP + Lat, and effective diameter(√ AP * Lat) to determine size specificdose estimate(SSDE) from the CT dose index volume(CTDIvol) recorded from the dose reports. Data were analyzed using SPSS v19. RESULTS: Total number of 5376 measurements was done. In some patients entire body circumference was not covered on either projection radiograph or transverse CT images; hence accurate measurement of AP and Lat diameters was not possible in 11%(278/2488) of locations. Forty one patients were off-centered with mean of 1.9 ± 1.8 cm(range: 0.4-7 cm). Conversion factors for attained diameters were not listed on AAPM look-up tables in 3%(80/2488) of measurements. SSDE values were significantly different compared to CTDIvol, ranging from 32% lower to 74% greater than CTDIvol. CONCLUSION: There is underestimation and overestimation of dose comparing SSDE values to CTDIvol. Localizer radiographs are associated with overestimation of patient size and therefore underestimation of SSDE.
基金financially supported by Special Funds of the State Environmental Protection Public Welfare Industry(201009049201309049)+1 种基金National Key Technology Research and Development Program of the Ministry of Science and Technology of China(2013BAI12B03)the Fundamental Research Funds for the Central Universities(2015JBM108)
文摘A survey involving 6103 participants from five Chinese provinces was conducted to evaluate the threshold value of urinary cadmium （UCd） for renal dysfunction as benchmark dose low （BMDL）. The urinary N-acetyl-13-D-glucosaminidase （UNAG） was chosen as an effect biomarker. The UCd BMDLs for UNAG ranged from 2.18μg/g creatinine （cr） to 4.26μg/g cr in the populations of different provinces. The selection of the sample population and area affect the evaluation of the BMDL. The reference level of UCd for renal effects was further evaluated based on the data of all 6103 subjects. With benchmark responses （BMR） of 10%/5%, the overall UCd BMDLs for males in the total population were 3.73/2.08 μg/g cr. The BMD was slightly lower in females, thereby indicating that females may be relatively more sensitive to Cd exposure than are males.
基金Supported by State Envivonment Protection Bureau and Chinese Nuclear Industry Corporation (Project No.90201001)
文摘This paper introduces the resident’s additional dose in bone-coal mining areas. The increase of the annual additional effective doses accepted by the residents living in the carbide-brick houses, the staffs working in the car-bide-brick houses and the miners working in the bone-coal mining areas of Hubei, Hunan, Jiangxi, Zhejiang and An-hui Provinces is caused by the rising of environmental radioactive level. The investigation of natural background ra-diation in the bone-coal mining areas indicated that both mining and utilizing bone-coal cause the rise of environ-mental radioactive level. The ranges of the annual additional effective dose accepted by the residents, staffs and min-ers is 1.9—6.8 mSv, 0.5—2.0 mSv and 8.2—71 mSv, and with an average of 3.8 mSv, 1 mSv and 40 mSv, respec-tively. The annual additional effective doses accepted by part residents and staffs exceed the dose limit of 1 mSv for public exposure, and part miners exceed the dose limit of 20 mSv for occupational exposure. And the contribution of dose caused by inhaled radon to the total additional effective dose is over 76%.
文摘目的 比较容积CT剂量指数(Volume CT Dose Index,CTDI_(vol))与基于水当量直径(Water Equivalent Diameter,WED)的体型特异性剂量估算值(Size-Specific Dose Estimate,SSDE),即SSDEWED,在儿童腹盆部辐射剂量衡量上的差异,探讨基于年龄预计算CTDI_(vol)、SSDEWED的可行性。方法 回顾性收集2021年1-12月行腹盆部检查的812例患儿CT影像学资料,记录其年龄、CTDIvol,测量感兴趣区(Region of Interest,ROI)面积(Area of ROI,AROI)及CT值(CT Value of ROI,CTROI)并计算SSDEWED,比较CTDIvol和SSDEWED在衡量辐射剂量上的差异;分析CTDI_(vol)、SSDEWED与年龄间相关性并建立回归方程,同时分析回归方程的一致性。结果 812例患儿腹盆部CTDI_(vol)为(2.90±1.20)mGy,SSDEWED为(5.64±1.90)mGy,二者间差异有统计学意义(P﹤0.001)。CTDI_(vol)、SSDEWED随着年龄的增加而增加,指数函数很好地拟合了CTDI_(vol)、SSDEWED与年龄间的相关性。实测CTDIvol为(2.90±1.20)mGy,计算CTDI_(vol)为(2.91±1.05)mGy,二者间差异无统计学意义(t=0.97,P=0.33);实测SSDEWED为(5.64±1.90)mGy,计算SSDEWED为(5.58±1.35)mGy,二者间差异亦无统计学意义(t=1.83,P=0.07)。基于年龄计算的CTDI_(vol)、SSDEWED与各实测值间均具有强相关性(相关系数分别为0.88、0.81)。结论 相较于CTDIvol,SSDEWED更能准确衡量儿童腹盆部辐射剂量,使用年龄来预计算患儿的辐射剂量指标,可以在检查前快速预估其辐射,对于辐射剂量更好的控制具有重要作用。
